Research On Fouling Detection Based On Ultrasonic Technology

Existing in various industrial processes, fouling is a common problem which causes negative impact, and the existed fouling threatens the safety of running machines and increases the costs of daily operation and maintenance. However, many fouling testing researches and methods have been carried out, no one is convenient and efficient. Ultrasonic technology has the advantages of rapidity, harmless and nondestructive testing which is also on-line and detecting abundant information.The UTDR method is adopted in this paper to study fouling testing in plates and pipelines. Based on the relative surveys and literatures, the principles and characteristics of ultrasonic technology are analyzed in this paper and UTDR (Ultrasonic Time-Domain Reflectometry) transmitting and receiving circuits are designed. According to the principles of UTDR, receivers of low resonance frequency are applied to testing thick fouling, receivers of high resonance frequency are used for testing thin fouling and de-noising filters are applied to echo signals by utilizing wavelet transform result. Due to the variation of physical properties of fouling and the differences of forming conditions and external conditions, it is hard to provide the physical properties. Thus, the speed of sound and thickness of fouling under the same operation conditions are calibrated, then the fouling can be tested by the calibrated data. The working environment of a specific condition is relatively stable, so the calibration experiment can be used for the quantitative analysis of fouling.The experiment shows that the quantitative or qualitative analysis of the forming condition of fouling are feasible and the effectiveness of testing fouling in plates and pipelines by using UTDR method.